The present invention relates to an acyl-neutral amino acid polyglycerin ester, and more perticularly to an N-long chain acyl-neutral amino acid polyglycerin ester in which at least one or more N-long chain acyl-neutral amino acid molecules are bonded via ester bonding to one molecule of polyglycerin having a degree of glycerin polymerization of 4 or more, and to a nonionic surfactant composition comprising, as an active ingredient, at least one kind of such esters and a cosmetic composition or a percutaneous preparation comprising, as a nonionic surfactant ingredient, at least one kind of such esters in an effective amount.
Incidentally, the acyl-neutral amino acid polyglycerin ester is, as can be seen from its structural formula given later, a nonionic compound, and shows surface activity (emulsifying activity). For these reasons it is a kind of nonionic surfactant.
Heretofore, anionic surfactants as used in soap emulsification in the past have been generally used as surfactants in producing emulsified products such as cosmetic compositions, percutaneous preparations, and the like, but, recently, ethylene oxide-based nonionic surfactants have become used popularly for that purpose. However, the safety of ethylene oxide-based nonionic surfactants is considered problematic in that they often irritate sensitive skins. Many consumers who take an increasing interest in the safety of products therefore desire ethylene oxide-free nonionic surfactants. In particular, they desire products of natural materials.
As nonionic surfactants which are less irritative or the like, and therefore highly safe are widely known polyglycerin fatty acid esters which are esterified products of polyglycerins with fatty acids.
As is well known, fatty acids are natural substances, and polyglycerins are condensation products of glycerin which is also a natural substance. Polyglycerin fatty acid esters are preferred to ethylene oxide-based nonionic surfactants in view of their safety, and the former can be produced easily on an industrial scale. However, conventional polyglycerin fatty acid esters cannot, when used in cosmetic compositions such as milky lotion, cream and the like or in percutaneous preparations, be always sensorially satisfactory, as they are often sticky or the like.
On the other hand, as less irritative and highly safe natural surfactants are widely used N-long chain acyl-neutral amino acids which are acylated products of amino acids with fatty acids. Some compounds wherein such N-long chain acyl-neutral amino acids are introduced, are known as nonionic surfactants usable as emulsifiers, etc. For example, in Japanese Patent Publication (kokoku) No. 62991/1979, it is disclosed that alcohol esters of N-long chain acyl-neutral amino acids are favorable as surfactants in the Perfume and cosmetic field. Alcohols referred to therein include polyalcohols, polyoxyalkylene-polyalcohols, etc. For example, mono(N-lauroyl-N-methyl-xcex2-alanine) glycerin ester, di(N-lauroyl-N-methyl-xcex2-alanine) glycerin ester and others described in the examples in the patent publication are among those N-long chain acyl-neutral amino acid glycerin esters noted above, and their safety is good.
Though having good safety, however, those monoglycerin and diglycerin esters are still problematic in that, when used in cosmetic compositions or percutaneous preparations, they can not be always satisfactory for the sensorial feel. For example, in actual use of such cosmetic compositions or percutaneous preparations comprising such esters, they are poorly spread on the skin and they are not smooth and are poorly compatible with the skin while giving little refreshing feel when they are applied to the skin, whereas they are often sticky and give little refreshing feel, after they have been applied to the skin.
In that situation of the prior art, now are desired nonionic surfactants which can be more excellent emulsifier and are safer and which, when incorporated into cosmetic compositions or percutaneous preparations, can provide sensorially satisfactory compositions or preparations.
The object of the present invention is to provide nonionic surfactants which are safer than conventional ones and which feel good in their use.
Given that situation noted above, the present inventors have assiduously studied and, as a result, have found that, when an N-long chain acyl-neutral amino acid polyglycerin ester composed of a polyglycerin having a degree of polymerization of not smaller than 4 and an N-long chain acyl-neutral amino acid having a long chain acyl group with from 6 to 22 carbon atoms is used as an emulsifier or the like in cosmetic composions or percutaneous preparations, its gives a good feel in use of those cosmetic compositions or percutaneous preparations. On the basis of these findings, they have completed the present invention.
Specifically, the invention relates to an N-long chain acyl-neutral amino acid polyglycerin ester, which is composed of a polyglycerin having a degree of glycerin polymerization of not smaller than 4 and an N-long chain acyl-neutral amino acid having an acyl group with from 6 to 22 carbon atoms, and which is represented by the following general formula (I): 
wherein at least one of plural X""s represents an N-long chain acyl-neutral amino acid residue, and the remaining X""s each independently represent a hydrogen atom or an N-long chain acyl-neutral amino acid residue, and n represents an integer of not smaller than 2, and wherein the acyl group in each N-long chain acyl-neutral amino acid residue is a straight-chain or branched-chain and saturated or unsaturated acyl group having from 6 to 22 carbon atoms.
The present invention relates also to a nonionic sufactant composition comprising, as an active ingredient, at least one kind of such N-long chain acyl-neutral amino acid polyglycerin ester in an effective amount as well as to a cosmetic composition and a percutaneous preparation comprising, as a nonionic surfactant ingredient, at least one kind of such N-long chain acyl-neutral amino acid polyglycerin ester in an effective amount.
The invention will be described in detail hereinunder.
The long chain acyl group in the N-long chain acyl-neutral amino acid polyglycerin ester of the present invention is a straight-chain or branched-chain, saturated or unsaturated one having from 6 to 22 carbon atoms. As preferred examples of the acyl group may be mentioned acyl groups derivable from capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, linolic acid, linolenic acid, oleic acid, isostearic acid, 2-ethylhexanoic acid, coconut oil fatty acids, beef tallow fatty acids, hardened beef tallow fatty acids, etc.
The neutral amino acid (residue) is not specifically limited, and includes, for example, glycine, alanine, valine, leucine, isoleucine, serine, threonine, proline, xcex2-alanine, aminobutyric acid, sarcosine, N-methyl-xcex2-alanine, etc. Especially preferred are glycine, alanine, xcex2-alanine, aminobutyric acid, sarcosine and N-methyl-xcex2-alanine.
The polyglycerin should have a degree of glycerin polymerization of not smaller than 4, and preferably from 4 to 10. Polyglycerins having a degree of glycerin polymerization of 3 or less are undesirable, since their esters could not give a good sensual feel.
One or more molecules of the N-long chain acyl-neutral amino acid may be introduced into one molecule of the polyglycerin via ester bonding. For example, tetraglycerin has 6 esterifiable hydroxyl groups in one molecule, in which a part or all of those hydroxyl groups may be esterified with the N-long chain acyl-neutral amino acid. Various types of nonionic surfactants having different HLB (hydrophile-lipophile balance) values can be produced, for example, by properly varying the degree of polymerization of the polyglycerin to be modified and also the number of molecules of the acyl-neutral amino acid to be bonded thereto, in accordance with the intended use.
The N-long chain acyl-neutral amino acid polyglycerin esters of the invention can be produced, for example, by heat-esterifying an N-long chain acyl-neutral amino acid with a polyglycerin under normal or reduced pressure for dehydration condensation (see Example 22 and others mentioned hereinunder). They may be also produced through azeotropic dehydration condensation reaction or transesterification reaction (see Example 1 and others mentioned hereinunder). It is also possible to addition-react glycidol or epichlorohydrin with an N-long chain acyl-neutral amino acid or N-long chain acyl-neutral amino acid glycerin ester to produce the N-long chain acyl-neutral amino acid polyglycerin esters of the present invention. Crude N-long chain acyl-neutral amino acid polyglycerin ester thus produced can be purified by steam-deodorizing, decolorizing with the use of an adsorbent such as activated carbon, desalting by washing with water or an aqueous inorganic salt solution, removing such impurities as unreacted polyglycerin, acylamino acid and the like with the use of an organic solvent such as hexane, or the like.
The N-long chain acyl-neutral amino acids and their glycerin esters to be used for producing such N-long chain glycidol, epichlorohydrin or the like. Commercially-available polyglycerins may be used according to the present invention, which include, for example, xe2x80x9cPolyglycerin #310xe2x80x9d (tetraglycerin), xe2x80x9cPolyglycerin #500xe2x80x9d (hexaglycerin), xe2x80x9cPolyglycerin #750xe2x80x9d (decaglycerin), all the products being ex Sakamoto Pharmaceutical Industry Co., etc.
In general, a polyglycerin product produced in those methods noted above are not composed of a single molecular species. For example, as for a tetraglycerin product, it often contains triglycerin, pentaglycerin and any other polyglycerins, and even non-reacted, starting glycerin. The polyglycerins thus produced may be purified to remove the other not-intended polyglycerins and the non-reacted glycerin therefrom, prior to being reacted with N-long chain acyl-neutral amino acids. If possible, however, they may be directly reacted with N-long chain acyl-neutral amino acids without being specifically purified.
An N-long chain acyl-neutral amino acid polyglycerin ester product of the present invention produced from an N-long chain acyl-neutral amino acid and a polyglycerin according to the methods mentioned above is usually in the form of a mixture of the intended ester and esterified polyglycerin compounds of which the degree of polymerization differs from the intended one, where the starting polyglycerins are not specifically purified prior to being reacted with the acids. However, for acyl-neutral amino acid polyglycerin esters are not always needed to be single compounds but may be in the form of mixtures of two or more of them that differ in the type of the acyl group therein and/or in the type of the neutral amino acid moiety therein. In such case, N-long chain acyl-neutral amino acid polyglycerin ester thus produced is one where a plurality of N-long chain acyl-neutral amino acids are different from one another when a pourality of X""s represent a plurality of different N-long chain acyl-neutral amino acid residuces in the general structural formula (I) above. Further, an N-long chain acyl-neutral amino acid polyglycerin ester product thus produced is one composed of a mixture of a plurality of different molecular species, not of a single molecular species. In this sense, such mixture of N-long chain acyl-neutral amino acid polyglycerin esters can be called an nonionic surfactant xe2x80x9ccomposition.xe2x80x9d
In this connection, N-long chain acyl-neutral amino acids may be produced in any known method of, for example, so-called Schotten-Baumann reaction wherein a long-chain fatty acid halide is reacted with an amino acid in the presence of a basic catalyst (see Japanese Patent Publication (kokoku) No. 38681/1976, etc.).
The polyglycerins may be produced also in any known method of, for example, dehydration condensation reaction of glycerin, or polymerization reaction of glycerin analogues such as use in the cosmetic compositions and the percutaneous preparation of the present invention, the polyglycerin esters are not always needed to have a single degree of polymerization. Even such a mixture of different types of polyglycerin esters that differ in the degree of polymerization of the polyglycerin moiety therein, shows of course the nonionic surfactant activity the N-long chain acyl-neutral amino acid polyglycerin ester of the present invention shows. Therefore, such mixture is also included in the nonionic surfactant composition of the present invention. In addition, the N-long chain acyl-neutral amino acid polyglycerin ester of the present invention may be in the form of a mixture with any of monoglycerin esters, diglycerin esters and triglycerin esters of N-long chain acyl-neutral amino acids within the range not interfering with the nonionic surfactant activity thereof, and such mixture is also included in the scope of the nonionic surfactant composition of the present invention.
One or more kinds of the N-long chain acyl-neutral amino acid polyglycerin esters of the present invention can be used as an emulsifier (nonionic surfactant) in formulating cosmetic compositions and percutaneous preparations, such as face wash cream, face wash foam, cleansing cream, massage cream, cold cream, moisturizing cream, milky lotion, lotion, hand cream, pack, skin cosmetics for men, skin-protecting agents for babies, foundation, lipstick, press powder, eye shadow, stick-form hair vegetable-derived oily substances such as macadamia nut oil, jojoba oil, carnauba wax, sesame oil, cacao butter, palm oil, mink oil, haze wax, candelilla wax, whale oil, etc., petroleum and mineral-derived oily substances such as paraffins, microcrystalline wax, liquid paraffin, vaseline, ceresine, etc., as well as silicones such as methylpolysiloxane, polyoxyethylene-methylpolysiloxane, polyoxypropylene-methylpolysiloxane, poly(oxyethylene-oxypropylene)-methylpolysiloxane, methylphenylpolysiloxane, fatty acid-modified polysiloxanes, aliphatic alcohol-modified polysiloxanes, amino acid-modified polysiloxanes and other silicone polymers; resin acids, esters, ketones, etc.
The cosmetic compositions and the percutaneous preparations of the present invention may also optionally contain, any other various surfactants within the range not interfering with the effect of the N-long chain acyl-neutral amino acid polyglycerin ester or the nonionic surfactant composition of the present invention. The optional surfactants include, for example, anionic surfactants such as N-long chain acylamino acid salts, e.g., N-long chain acyl-acidic amino acid salts, N-long chain acyl-neutral amino acid salts, etc., N-long chain fatty acid acyl-N-methyltaurine salts, alkyl sulfates and their alkylene oxide adducts, fatty acid amide-ether sulfates, metal salts and weak base salts of fatty acids, sulfosuccinic acid-based surfactants, alkyl phosphates cream, hair liquid, hair-setting lotion, permanent-waving liquid, hair cream, hair lotion, hair mousse, shampoo, hair rinse, hair conditioner, body shampoo, solid detergent, liquid detergent, sweat-controlling agents, after-shaving cream, sunburn-protecting cream, sunburn-protecting oil, hair tonic, hair-growing agents, bathing agents, pharmaceutical compositions for external use, etc. The N-long chain acyl-neutral amino acid polyglycerin ester can be of course in the form of a nonionic surfactant composition of the present invention. The form of the cosmetic compositons and the percutaneous preparations is not specifically limited, and may be any type of emulsions, solutions, solubilizable mixtures, powdery dispersions, water-oil two-phase liquids, water-oil-powder three phase liquids, etc.
As the oily phase ingredients for the cosmetic compositions and the percutaneous preparations of the present invention are employable any ordinary ones within the range not interfering with the effect of the N-long chain acyl-neutral amino acid polyglycerin ester or the nonionic surfactant composition of the present invention. As such oily phase ingredients, there may be mentioned, for example, saturated or unsaturated fatty acids and higher alcohols to be derived therefrom, squalane, castor oil and their derivatives, bees wax, lanolins including liquid and pure lanolins, and their derivatives, cholesterol and its derivatives; animal and and their alkylene oxide adducts, alkyl ether-carboxylic acids, etc.; nonionic surfactants such as ether-type surfactants, e.g., glycerin ethers and their alkylene oxide adducts, etc., ester-type surfactants, e.g., glycerin esters and their alkylene oxide adducts, etc., ether-ester-type surfactants, e.g., sorbitan esters and their alkylene oxide adducts, etc., ester-type surfactants, e.g., polyoxyalkylene fatty acid esters, glycerin esters, fatty acid polyglycerin esters, N-long chain acyl-peptide polyglycerin esters, sorbitan esters, sucrose fatty acid esters, etc., alkylglucosides, hardened castor oil pyroglutamic acid diesters ad their ethylene oxide adducts, as well as nitrogen-containing nonionic surfactants, e.g., fatty acid alkanolamines, etc.; cationic surfactants such as aliphatic amines and their quaternary ammonium salts, e.g., alkylammonium chlorides, dialkylammonium chlorides, etc., aromatic quaternary ammonium salts, e.g., benzalkonium salts, etc., fatty acid acylarginine esters, etc.; as well as amphoteric surfactants such as betaine-type surfactants, e.g., carboxybetaines, etc., aminocarboxylic acid-based surfactants, imidazoline-based surfactants, etc.
The cosmetic compositions and the percutaneous preparations of the present invention may further contain, as an aqueous phase component, any of amino acids such as glycine, alanine, serine, threonine, arginine, glutamic acid, aspartic acid, leucine, valine, etc.; polyalcohols such as glycerin, ethylene glycol, 1,3-butylene glycol, propylene glycol, isoprene glycol, etc.; water-soluble polymers such as polyamino acids including polyglutamic acid and polyaspartic acid and their salts, polyethylene glycol, arabic gum, alginic acid salts, xanthane gum, hyaluronic acid, salts of hyaluronic acid, chitin, chitosan, water-soluble chitin, carboxyvinyl polymers, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyltrimethylammonium chloride, polydimethylmethylenepiperidium chloride, quaternary ammonium salts of polyvinylpyrrolidone derivatives, cationated proteins, collagen decomposates and their derivatives, acylated proteins, polyglycerins, amino acid polyglycerin esters, etc.; glycoalcohols such as mannitol, etc., and their alkylene oxide adducts; as well as lower alcohols such as ethanol, propanol, etc.
Any additives and pharmaceutical ingredients capable of being formulated in ordinary cosmetic compositions and percutaneous preparations can be incorporated into the cosmetic compositions and the percutaneous preparations of the present invention. For example, any of preservatives such as paraben derivatives, etc., as well as Perfumes, dyes, viscosity-controlling agents, pearly agents, antioxidants, microbicides, anti-inflammatory agents, analgesics, fungicides, keratin-softening and peeling agents, skin colorants, hormonic agents, UV absorbents, hair-growing agents, skin-whitening agents, sweat-controlling agents, sweat-deodorizing agents, vitamins, pH-controlling agents, pharmaceutical agents such as herbs, etc.
The amount of the N-long chain acyl-neutral amino acid polyglycerin ester or the nonionic surfactant composition comprising, as an active ingredient, at least one kind of such ester to be incorporated into the cosmetic compositions and the percutaneous preparations that may be prepared by suitably formulating the components noted above may vary, depending on the form of the products, but, in general, it may be from 0.01 to 100% by weight (the nonionic surfactant composition of the invention may be directly used as it is, for example, for makeup removal, without being combined with any other components), but preferably from 0.1 to 50% by weight,
The invention is described in more detail hereinunder with reference to the following Examples, which, however, are not intended to restrict the scope of the present invention.